What Is This Thing Swimming Around After Vacuuming?

[crumpybumpy]

Hi I have an 8.5 gallon tank with snails shrimp and 5 fish. I did a siphon vacuuming of my gravel and there were all these little creatures swimming around in the water???! They were the size of maybe a sesame seed and were buzzing around at a pretty fast clip. They were really too small to identify anatomical features but they looked kind of oval with maybe a small row of legs underneath...kind of remining me a little bit of a horseshoe crab without the tail of course. Any idea what they could be? I tried to take a picture and video but they were too small for my camera to focus on. Thanks.

 

[micko]

Could they be shrimp?

 

[Hermithall]

Could they be Seed Shrimp (Ostracod)? - do a google image search and see if you recognize them. Not sure if they are considered a pest or not in the aquarium.

 

[willowstwin]

+ 1 with micko... have your shrimp been breeding? hehe